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