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