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