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