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