Devin used a six string guitar tuned (low to high) EADGBE 
That's right! Standard tuning for this one... 

Riff A 

E---------------------------------| 
B-----------------0---------------| 
G-------------1-------1-----------| 
D---------4---------------4-------| 
A-----2-----------------------2---| 
E-0-------------------------------| 

This goes through five cycles of eight. 
Some repeats have variations as noted below. 

8th and 24th repeats 
E-------------------------------0-| 
B-----------------0---------------| 
G-------------1-------1-----------| 
D---------4---------------4-------| 
A-----2-----------------------2---| 
E-0-------------------------------| 

16th repeat 
E---------------------------------| 
B-----------------0---------------| 
G-------------1-------------------| 
D---------4-----------------------| 
A-----2---------------------------| 
E-0-------------------------------| 

On top of this riff, Devin stacks up other guitars as follows. 

guitar two strums the chord shape 

guitar three 
E-----------------------------------------------------------------| 
B-----------------------------------------------------------------| 
G-9-9-9-9-9-9-9-9-9-9-9-9-9-9-9-9-8-8-8-8-8-8-8-8-8-8-8-8-8-8-8-8-| 
D-----------------------------------------------------------------| 
A-7-7-7-7-7-7-7-7-7-7-7-7-7-7-7-7-6-6-6-6-6-6-6-6-6-6-6-6-6-6-6-6-| 
E-----------------------------------------------------------------| 

E-----------------------------------------------------------------| 
B-----------------------------------------------------------------| 
G-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-4-| 
D-----------------------------------------------------------------| 
A-2-2-2-2-2-2-2-2-2-2-2-2-2-2-2-2-2-2-2-2-2-2-2-2-2-2-2-2-2-2-2-2-| 
E---------------------------------0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-| 

guitar four 
E-----------------------------------------------------------------| 
B-5-5-5-5-5-5-5-5-5-5-5-5-5-5-5-5-4-4-4-4-4-4-4-4-4-4-4-4-4-7---5-| 
G-----------------------------------------------------------------| 
D-----------------------------------------------------------------| 
A-----------------------------------------------------------------| 
E-----------------------------------------------------------------| 

E-----------------------------------------------------------------------| 
B-5/7-7-7-7-7-7-7-7-7-7-7-7-7-7-7-12\-7-7/9-9-9-9-9-9-9-9-9-9-9-9-9-9-9-| 
G-----------------------------------------------------------------------| 
D-----------------------------------------------------------------------| 
A-----------------------------------------------------------------------| 
E-----------------------------------------------------------------------| 

Both guitar three and guitar four are strummed loosely, so with guitar 
three you have the high strings ringing out lightly beneath the octave 
shapes and with guitar four you have the high E string ringing out 
occasionally also. The trick is to play gently, this is a sweet song! 

Riff B 

E-------------------------0-----------------------0---------------| 
B---------0-------------0---0-------------0---------0-------0-----| 
G-------3---3---------3-------3---------3---3---3-----3---3---3---| 
D-----4-------4-----4-----------4-----4-------4---------4-------4-| 
A---4-----------4-------------------4-----------------------------| 
E-2---------------2---------------2-------------------------------| 

then strum that nice E chord from Riff A 
then strum the shord from Riff B 
then strum the chord from Riff A again 

These are the chord shapes for the "baby blue" part 

E----0----0----| 
B----0----0----| 
G----4----3----| 
D----4----4----| 
A--------------| 
E----4----4----| 

Alternate between those and the E chord from Riff A until 

Riff C (hold the shape, pick gently and let the notes ring out) 

E-----------------------------| 
B-----------------------------| 
G-----------------------------| 
D---------------5-----5-------| 
A-------6---6-----6-----6---6-| 
E-4---4---4---4-----4-----4---|