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