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