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