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