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