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