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