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