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