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