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