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