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