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