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