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)(11,14)(12,15)(13,16)(17,18,21,20)(19,23,24,22)(25,26,29,32)(27,30,33,37)(28,35,36,31)(34,40,39,38)(1,3,6,5)(2,7,8,4)(9,11,13,12)(10,14,16,15)(18,20)(22,23)(27,33)(30,37)(34,39)(38,40)(2,8)(4,7)(9,10,13,16)(11,14,12,15)(17,18,21,20)(19,23,24,22)(25,27,29,33)(26,30,32,37)(28,34,36,39)(31,38,35,40)(1,4)(2,3)(5,8)(6,7)(9,10)(11,14)(12,15)(13,16)(17,19,21,24)(18,22,20,23)(25,26)(27,30)(28,31)(29,32)(33,37)(34,38)(35,36)(39,40)(1,5,6,3)(2,4,8,7)(9,12,13,11)(10,15,16,14)(17,20,21,18)(19,23,24,22)(25,28,29,36)(26,31,32,35)(27,34,33,39)(30,38,37,40)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.