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