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