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