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