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