Useful chimera commands
You might like to make a small molecules (eg. HEM) part of the surface of the protein instead of separate:
surfcat one #1:1-290 surf one probeRadius 1.4
You might want to color by partial charge:
rangecolor charge,a min red 0 white max blue sel rangecolor charge,a -1.0 red 0.0 white 1.0 blue sel
This command will color the selected atoms by there charge.
Here are some tutorials: