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