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