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