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