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