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)(15,22)(16,21)(17,23)(18,20)(19,26)(24,25)(27,28)(5,6,8,9)(7,10,11,12)(13,15)(14,19)(16,24)(17,25)(18,26)(20,22)(21,28)(23,27)(1,3,4,2)(14,20)(17,21)(19,22)(25,28)(5,7,8,11)(6,10,9,12)(13,16,18,23)(14,21,20,17)(15,24,26,27)(19,28,22,25)(13,15)(14,22)(16,27)(17,25)(18,26)(19,20)(21,28)(23,24) involution — undirected(13,17,18,21)(14,23,20,16)(15,25,26,28)(19,27,22,24)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.