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