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