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