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