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