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