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