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