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