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