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