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