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