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