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