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