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