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