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