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)(15,19)(16,17)(18,20)(21,22)(23,27)(24,31)(25,33)(26,29)(28,34)(30,36)(32,35) involution — undirected(6,8)(10,11)(13,15)(14,18)(16,19)(17,20)(21,23,26,24)(22,27,29,31)(25,32,34,30)(28,36,33,35)(6,8)(7,12)(14,16)(15,20)(21,24,26,23)(22,27,29,31)(25,32,34,30)(28,35,33,36)(1,2)(3,4)(5,7,9,12)(6,10,8,11)(13,15)(14,18)(16,19)(17,20)(21,22)(23,27)(24,31)(25,28)(26,29)(30,35)(32,36)(33,34)(5,8,9,6)(7,10,12,11)(13,16,17,14)(15,18,20,19)(21,25)(22,28)(23,30)(24,32)(26,34)(27,35)(29,33)(31,36)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.