Here is what another highly visual book Making Work Visible did. The author created an audio companion pdf. You could in your case put it behind some kind of paywall or something? I don't know. But having listened to the Audio bookm and reading on kindle - it was pretty hard to visualize this stuff until I accessed the companion. In fact i may have tried in kindle also. If memory serves me, even reading it on kindle was a pain as it was black and white instead of color and you can't zoom in. So in that case the pdf companion was also useful.

Book: