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)(23,30)(24,26)(25,29)(27,31)(28,33)(32,35)(34,36) involution — undirected(1,2)(3,4)(13,15,16,19)(14,17,18,20)(22,26)(24,33)(27,34)(28,29)(30,35)(32,36)(2,4)(6,9)(10,12)(21,23)(22,27)(24,32)(25,31)(26,34)(28,35)(29,30)(33,36) involution — undirected(5,7,8,11)(6,10,9,12)(14,18)(17,20)(23,31)(27,30)(32,36)(34,35)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.