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