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