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