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