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