One vertex per element, one color per generator, with an edge from x to x·s.
(5,6)(7,10)(8,9)(11,12)(13,14)(15,17)(16,18)(19,20)(21,22,26,29)(23,30,33,36)(24,28,25,34)(27,31,35,32)(1,2,3,4)(6,9)(10,12)(13,15,16,19)(14,17,18,20)(2,4)(5,7,8,11)(6,10,9,12)(21,23,25,32,26,33,24,31)(22,27,28,30,29,35,34,36)(7,11)(10,12)(14,18)(17,20)(21,24,26,25)(22,28,29,34)(23,31,33,32)(27,30,35,36)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.