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