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