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