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