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