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