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