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)(11,19)(12,14)(13,17)(15,18)(16,20)(21,24)(22,23)(25,26)(27,33)(28,36)(29,32)(30,35)(31,37)(34,39)(38,40) involution — undirected(1,3,5,4)(2,6,8,7)(9,11,13,20)(10,16,17,19)(12,22,18,24)(14,21,15,23)(27,34)(28,37)(31,36)(33,39)(1,3,5,4)(2,7,8,6)(9,12,15,17,13,18,14,10)(11,16,23,22,20,19,21,24)(25,27,28,35,29,34,37,40)(26,30,31,33,32,38,36,39)(1,4,5,3)(2,7,8,6)(10,17)(12,18)(16,19)(22,24)(27,34)(30,38)(33,39)(35,40)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.