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