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