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