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