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