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