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