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