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