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