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