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)(13,14,17,20,18,21,16,25)(15,22,24,27,23,28,26,19)(2,3)(5,6)(7,11)(8,10)(9,12)(15,23)(19,27)(22,28)(24,26) involution — undirected(5,7,8,12)(6,9,10,11)(13,15)(14,19)(16,24)(17,26)(18,23)(20,28)(21,27)(22,25)(1,3,4,2)(7,12)(9,11)(15,23)(19,27)(22,28)(24,26)(6,10)(9,11)(13,16,18,17)(14,20,21,25)(15,24,23,26)(19,28,27,22)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.