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