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