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