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