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