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