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