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