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