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