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