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