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