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