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