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