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