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