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