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