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