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