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