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