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)(11,16,22,31)(12,23)(13,15)(14,19)(17,25)(18,26)(20,33,34,38)(21,27,36,30)(24,28)(29,39,40,35)(32,37)(2,5)(3,7)(10,15,19,18)(12,24)(16,27,31,30)(17,23,32,28)(20,34)(25,37)(29,33,40,38)(35,39)(1,3,4,7)(2,6,5,8)(9,11,13,21,14,22,26,36)(10,16,18,30,19,31,15,27)(12,20,25,35,24,34,37,39)(17,29,23,33,32,40,28,38)(2,5)(6,8)(9,12,13,25,14,24,26,37)(10,17,18,23,19,32,15,28)(11,20,21,35,22,34,36,39)(16,29,30,33,31,40,27,38)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.