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