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