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)(14,18)(16,24)(19,21)(20,25)(23,26)(27,28) involution — undirected(5,6)(7,11)(8,10)(9,12)(13,14)(15,21)(16,25)(17,20)(18,24)(19,26)(22,28)(23,27) involution — undirected(2,4)(5,7)(6,9)(8,12)(10,11)(15,22)(19,27)(21,28)(23,26) involution — undirected(7,12)(9,11)(13,15,17,22)(14,19,20,27)(16,26,24,23)(18,21,25,28)(6,10)(9,11)(14,20)(18,25)(19,27)(21,28) 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.