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