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