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