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