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