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