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