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