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