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