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