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