One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,4)(9,10,17,32,13,28,31,40,16,22,14,21,15,20,29,34)(11,18,27,38,26,35,33,39,12,25,24,36,23,37,30,19)(2,4)(5,6)(7,8)(9,11,14,24,13,26,29,30,16,12,17,27,15,23,31,33)(10,18,21,36,28,35,34,19,22,25,32,38,20,37,40,39)(6,8)(9,12)(10,19)(11,16)(13,26)(14,30)(15,23)(17,33)(18,34)(20,38)(21,35)(22,39)(24,29)(25,40)(27,31)(28,36)(32,37) involution — undirected(2,4)(9,13,16,15)(10,20,22,28)(11,23,12,26)(14,29,17,31)(18,35,25,37)(19,38,39,36)(21,40,32,34)(24,33,27,30)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.