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