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