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