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