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)(25,26,32,35,31,36,29,30)(27,34,37,40,28,33,39,38)(1,3,4,7)(2,5,6,8)(9,11,14,21)(10,15,17,18)(12,19,13,20)(16,23,22,24)(25,27)(26,33)(28,31)(29,39)(30,40)(32,37)(34,36)(35,38)(2,6)(5,8)(9,12,14,13)(10,16,17,22)(11,19,21,20)(15,23,18,24)(25,28,31,27)(26,34,36,33)(29,37,32,39)(30,38,35,40)(9,12,14,13)(10,16,17,22)(11,20,21,19)(15,24,18,23)(25,29,31,32)(26,35,36,30)(27,37,28,39)(33,40,34,38)(9,13,14,12)(10,16,17,22)(11,20,21,19)(15,23,18,24)(25,30,29,36,31,35,32,26)(27,38,39,33,28,40,37,34)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.