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)(26,31)(27,28)(34,35)(37,38)(9,11)(10,14)(12,18)(13,19)(15,22)(16,17)(20,23)(21,24)(25,26,29,31)(27,36,28,33)(30,34,39,35)(32,38,40,37)(2,5)(6,8)(25,27)(26,32)(28,29)(30,38)(31,40)(33,35)(34,36)(37,39) involution — undirected(9,12,13,21)(10,15,16,20)(11,18,19,24)(14,22,17,23)(25,28,29,27)(26,33,31,36)(30,38,39,37)(32,34,40,35)(1,3,4,7)(2,6,5,8)(11,19)(14,17)(18,24)(22,23)(26,34)(30,39)(31,35)(32,36)(33,40)(37,38)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.