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