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