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