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