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