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