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