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