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