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