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