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