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