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