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