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