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