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