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