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