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