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