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