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