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