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