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