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