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