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