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