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