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