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