There was published a book back in the '70s with the charts for one
of Chicago's albums containing "Colour My World".  I've forgotten
the album name, but it also had "Saturday in the Park", and "Just You
and Me".

As I remember it had all the piano, guitar, flute, horn, etc.  parts
written out, including the solos.  Unfortunately, if I still have it,
it's well hidden.  :-(  You may still be able to find it in a (used?)
music shop.

Mike Blackwell
mblackwell@wallace.com