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