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