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