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