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