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