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