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