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