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