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