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