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