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