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