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