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