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