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