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