Riff 1:
E|--------------------------------------------|
B|--------------------------------------------|
G|-22222222-----------------------------------|
D|-22222222-55555555-77777777-555555-33-------|
A|-00000000-33333333-55555555-333333-11-------|
E|-------------------------------------| x's 2-|

Riff 2:
E|-------------------------------|
B|-------------------------------|
G|-22---2-------22---2-----------|
D|-22-5-2-5-7-5-22-5-2-5---------|
A|-00-3-0-3-5-3-00-3-0-3-5-------|
E|-----------------------3| x's 8-|

Riff 1

Riff 2

Riff 1 x's 4

Riff 3: Not 100% about this part, but sounds close.
E|----------------------|
B|----------------------|
G|----------------------|
D|-2--------------------|
A|-2--3--4--5-3-5-------|
E|-0--4--5--3-1-3| x's 6-|