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