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