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