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)(11,16)(12,13)(14,15)(17,18)(19,23)(20,24)(21,22)(25,26,29,30)(27,33,34,31)(28,32,36,37)(35,39,40,38)(2,6)(4,7)(10,15)(13,16)(18,21)(19,24)(26,30)(27,34)(28,36)(38,39) involution — undirected(9,11,14,12)(10,16,15,13)(17,19,22,24)(18,23,21,20)(25,26)(27,31)(28,32)(29,30)(33,34)(35,38)(36,37)(39,40)(1,3)(2,4)(5,8)(6,7)(9,12,14,11)(10,13,15,16)(17,20)(18,19)(21,24)(22,23)(25,27,29,34)(26,31,30,33)(28,35,36,40)(32,38,37,39)(1,4)(2,3)(5,7)(6,8)(9,13)(10,11)(12,15)(14,16)(17,21,22,18)(19,20,24,23)(25,28)(26,32)(27,35)(29,36)(30,37)(31,38)(33,39)(34,40)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.