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