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