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)(12,25,27,34)(13,29)(14,17)(15,19)(16,23)(18,28,33,26)(21,31)(22,37,38,30)(24,32)(35,36,40,39)(2,5)(6,7)(9,11,13,23,14,24,15,21)(10,16,19,20,17,31,29,32)(12,22,28,39,27,38,26,36)(18,30,34,35,33,37,25,40)(1,3,4,8)(2,6,5,7)(10,17)(11,21)(12,26)(13,15)(16,20)(18,34)(22,38)(23,24)(25,33)(27,28)(31,32)(35,40)(3,8)(6,7)(9,12)(10,18)(11,22)(13,28)(14,27)(15,26)(16,30)(17,33)(19,34)(20,35)(21,36)(23,39)(24,38)(25,29)(31,37)(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.