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