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)(28,31)(29,32)(30,35)(34,39)(36,38)(37,40)(9,11,14,12)(10,16,20,24)(13,23,15,21)(17,19,22,18)(25,27)(26,30)(28,35)(29,34)(31,33)(32,38)(36,37)(39,40)(2,5)(6,8)(9,12,14,11)(10,17,20,22)(13,23,15,21)(16,19,24,18)(27,34)(29,37)(30,38)(32,40)(33,39)(35,36)(1,3,4,7)(2,6,5,8)(10,18)(13,15)(16,17)(19,20)(21,23)(22,24)(26,31)(30,33)(32,40)(38,39)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.