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