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