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