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)(25,26,32,35)(27,31,34,40)(28,30,29,33)(36,38,37,39)(2,5)(6,8)(9,11,15,22)(10,16,20,21)(12,19,13,23)(14,17,24,18)(25,27,32,34)(26,31,35,40)(28,37,29,36)(30,39,33,38)(1,2,4,5)(3,6,7,8)(9,12,15,13)(10,17,20,18)(11,19,22,23)(14,16,24,21)(25,28,32,29)(26,33,35,30)(27,36,34,37)(31,39,40,38)(3,7)(6,8)(9,13,15,12)(10,18,20,17)(11,19,22,23)(14,16,24,21)(25,29,32,28)(26,33,35,30)(27,37,34,36)(31,39,40,38)(1,2)(3,6)(4,5)(7,8)(9,11)(10,16)(12,23)(13,19)(14,17)(15,22)(18,24)(20,21)(25,30,32,33)(26,28,35,29)(27,38,34,39)(31,36,40,37)(1,3)(2,6)(4,7)(5,8)(9,14,15,24)(10,19,20,23)(11,17,22,18)(12,16,13,21)(25,31)(26,34)(27,35)(28,39)(29,38)(30,36)(32,40)(33,37)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.