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)(15,20)(16,22)(17,23)(18,21)(19,24)(25,27)(26,28) involution — undirected(1,2)(3,4)(5,6)(7,11)(8,10)(9,12)(13,15)(14,20)(16,17)(18,26)(19,25)(21,28)(22,23)(24,27) involution — undirected(5,7,8,12)(6,9,10,11)(14,21)(15,25)(17,18)(20,22)(23,24)(27,28)(2,4)(7,12)(9,11)(13,16,19,26)(14,22,24,28)(15,17,25,18)(20,23,27,21)(6,10)(9,11)(13,17,19,18)(14,21,24,23)(15,26,25,16)(20,22,27,28)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.