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