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