I forgot that the purpose of your site is comparing the number of mults. A more compatible idea is to rearrange the nodes so that any repeated squaring is always in a single row at the top. The graph would have the same nodes and connectivity, but a more structured flow. If I ever make my own comparison of polynomial evaluation strategies I'll do manual layout.

For completeness: To apply my original idea to R&W9 you would have 5 nodes labeled x, each with one arrow out, two nodes labeled x^2, each with no arrows in and one arrow out, one node labeled x^4 with no arrows in and one arrow out, one node labeled x^8 with no arrows in and one arrow out. Three missing mults, but way fewer crossings, not what you want.