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