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