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