MAIN RIFF
E|--------------------------------|
B|---6br46---4-------4------------|
G|---------------3-5----3-5-------|
D|--------------------------3-5---|
A|------------------------------3-|
E|--------------------------------|

After 4 runs the second guitar starts (Clapton), whose runs have a different ending ech time. 
I've tabbed most of them. Do improvise!

   Start of riff    Ending 1               Ending 2                   Ending 3
E|----------------|----------------------|--------11-------11-------|-11----------11--------------|
B|----------------|-------11-13----11-13-|---11h13----11h13---------|----13-11-13--------13p11-13-|
G|-14br1214b-12---|----12-------12-------|--------------------10----|-----------------------------|
D|----------------|----------------------|-----------------------13-|-----------------------------|
A|----------------|----------------------|--------------------------|-----------------------------|
E|----------------|----------------------|--------------------------|-----------------------------|
   Ending 4                 Ending 5
E|----------------------|---------------------|
B|-------11--13----11---|---------------------|
G|-10-12--------12------|-------10--12--------|
D|----------------------|-10-13--------13-10--|
A|----------------------|---------------------|
E|----------------------|---------------------|