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