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)(13,14,17,21)(15,22,25,19)(16,26,18,20)(23,27,28,24)(1,2)(3,4)(6,10)(11,12)(13,15,17,25)(14,19,21,22)(16,24,18,27)(20,23,26,28)(2,4)(13,14)(15,19)(16,26)(17,21)(18,20)(22,25)(23,27)(24,28) involution — undirected(2,4)(5,7,9,8)(6,11,10,12)(13,14)(15,23)(16,20)(17,21)(18,26)(19,27)(22,24)(25,28)(5,8,9,7)(6,11,10,12)(13,16,17,18)(14,20,21,26)(15,24,25,27)(19,23,22,28)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.