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