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