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