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