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