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