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