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