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