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