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