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