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