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