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