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