Riff A (repeats several times)
E|------------------|
B|------------------|
G|---------------5--|
|-7777775555555555-|
|-7777775555555535-|
|-55555533555555-3-|
   . . . . . . . 

 Riff B (played 4 times)
E|------|
B|------|
G|-5----|
|-5-57-|
|-3-57-|
E|---35-|

The variation of Riff A played after Riff B is simply the same
thing, except without palm muting and straight triplet picking
(it's in 12/8 time).

Then Riff A is played again except ALL palm muted.

The song then changes to 4/4 time.

 Riff C (played several times under a lead)
E|------------------------------------------------------------------|
B|------------------------------------------------------------------|
G|-5555555555555555-------------------------------------------------|
|-5555555555555555555555555555555533333333333333335555555555555555-|
|-3333333333333333555555555555555533333333333333335555555555555555-|
E|-----------------333333333333333311111111111111113333333333333333-|
 (each chord is played 16 times, twice per beat)

 Lead over Riff C
E|-----------------------------------------|
B|-----------------------------------------|
G|-9--12--10-9-7--7-9-7--7-5-5-4-5--7-9-7--|
D|-----------------------------------------|
A|-----------------------------------------|
E|-----------------------------------------|

E|------------------------------------------------|
B|------------------------------------------------|
G|-5-/12--10-9-10-5-/12--10-9-1010-9--10-12-1097--|
D|------------------------------------------------|
A|------------------------------------------------|
E|------------------------------------------------|

 There are some variations to Riff C, such as palm muting.  But the
 chords stay the same, so figure it out for yourself.  Also, this
 riff is played a couple times...it is just a stripped down version
 of the lead.

E|---------------------------------------|
B|---------------------------------------|
G|-9---------7-----------5----------7----|
D|---------------------------------------|
A|---------------------------------------|
E|---------------------------------------|