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