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