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