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