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