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