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