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