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