One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,4)(5,6)(7,10)(8,9)(11,12)(21,22)(23,28)(24,33)(25,35)(26,30)(27,31)(29,34)(32,36) involution — undirected(6,9)(10,12)(13,14,16,18)(15,19,20,17)(21,23,25,31,26,32,34,24)(22,27,29,28,30,33,35,36)(2,4)(13,15,16,20)(14,17,18,19)(5,7,8,11)(6,10,9,12)(21,24,34,32,26,31,25,23)(22,28,35,27,30,36,29,33)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.