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)(11,19)(12,13)(14,17)(15,18)(16,22)(20,24)(21,23)(27,29)(31,33)(35,36)(38,39) involution — undirected(1,2,4,6)(3,5,8,7)(9,11)(10,16)(12,20)(13,21)(14,23)(15,22)(17,24)(18,19)(25,26,30,34)(27,31,29,33)(28,32,37,40)(35,38,36,39)(1,2)(3,5)(4,6)(7,8)(9,12,15,14)(10,17,18,13)(11,20,22,23)(16,24,19,21)(25,27,30,29)(26,31,34,33)(28,36,37,35)(32,39,40,38)(1,3)(2,5)(4,8)(6,7)(9,13,15,17)(10,12,18,14)(11,21,22,24)(16,20,19,23)(25,28,30,37)(26,32,34,40)(27,35,29,36)(31,38,33,39)(9,14,15,12)(10,17,18,13)(11,20,22,23)(16,21,19,24)(25,26)(27,31)(28,32)(29,33)(30,34)(35,38)(36,39)(37,40)(9,11)(10,16)(12,20)(13,21)(14,23)(15,22)(17,24)(18,19)(25,29,30,27)(26,33,34,31)(28,36,37,35)(32,39,40,38)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.