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)(11,19)(12,23)(13,17)(14,28)(15,21)(16,26)(18,27)(20,34)(22,30)(24,38)(25,37)(29,39)(31,40)(32,35)(33,36)(2,5)(6,7)(9,11)(10,15)(12,24)(13,21)(14,22)(16,29)(17,19)(18,30)(20,25)(23,34)(26,35)(27,36)(28,33)(31,32)(37,38)(39,40) involution — undirected(9,12,14,26,13,25,27,40)(10,16,18,23,17,31,28,37)(11,20,22,35,21,24,36,39)(15,29,30,38,19,32,33,34)(1,3,4,8)(2,6,5,7)(10,17)(11,21)(16,31)(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.