Since you're trying to illustrate that many different muscles I think you should make each muscle group a specific color. It makes it easier to read, and makes you think a bit about what the bumps you see are and where they belong. It also forces you to analyze instead of copying.

Nice study Kako! I feel you coul do a bit more work on your triceps specially the lateral head, it's lines are too sharp and pointy, and the long head is too small and high up. You also seemed to have mistaken part of the pecs with the shoulder, there is a shy line there separating both. You have great gesture, keep up the good work!