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)(11,16)(12,23,25,36)(13,18)(14,28)(15,19)(17,26,35,27)(20,37,38,34)(21,31)(22,33)(24,40,39,30)(29,32)(2,5)(6,7)(9,11,13,21,15,22,14,29)(10,16,18,31,19,33,28,32)(12,24,27,20,25,39,26,38)(17,34,36,40,35,37,23,30)(2,5)(6,7)(9,12,13,27,15,25,14,26)(10,17,18,36,19,35,28,23)(11,20,21,39,22,38,29,24)(16,30,31,34,33,40,32,37)(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.