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