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