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