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