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