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