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