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