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