Here's a page from Xenakis's notebooks, which, if I'm reading it right, shows him working through the colour coding system for some of his scores:
Just stumbled upon these scans, some more scores by Roland Kayn.
Kayn is the absolute best
Just managed to track down a copy of this book (finally):Sense Sound Sound Sense
Will post some pics or track down online versions of my fav scores when I get a chance
Share a review when you finish if you can!