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