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