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