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