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