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