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