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