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