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