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