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