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