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