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