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