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