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