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