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