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