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