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