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