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