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