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)(12,16)(13,22)(14,17)(15,21)(19,24)(20,23)(25,26,29,31)(27,35,37,32)(28,33,38,39)(30,34,36,40)(1,3,5,4)(2,6,7,8)(9,11)(10,15)(12,19)(13,20)(14,21)(16,23)(17,18)(22,24)(26,31)(27,28)(30,36)(32,33)(35,39)(37,38)(1,4,5,3)(2,6,7,8)(9,12,14,13)(10,16,17,22)(11,19,21,20)(15,23,18,24)(25,27)(26,32)(28,36)(29,37)(30,38)(31,35)(33,34)(39,40)(9,13,14,12)(10,16,17,22)(11,20,21,19)(15,23,18,24)(11,21)(15,18)(19,20)(23,24)(25,28,29,38)(26,33,31,39)(27,36,37,30)(32,34,35,40)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.