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