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