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