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