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