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