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