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