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