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