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