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