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