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