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