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