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