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