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