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