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