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