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