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