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