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