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