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