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