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