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