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