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