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