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