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