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