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