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