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