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