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)(23,27)(25,28) involution — undirected(5,6,8,10)(7,11,12,9)(13,15)(14,18)(16,19)(17,20)(21,22,24,26)(23,25,27,28)(5,6,8,10)(7,9,12,11)(13,15,17,20)(14,19,16,18)(21,23)(22,25)(24,27)(26,28)(1,2,3,4)(5,6)(7,11)(8,10)(9,12)(13,15)(14,18)(16,19)(17,20)(21,22)(23,25)(24,26)(27,28)(5,7,8,12)(6,9,10,11)(13,16,17,14)(15,18,20,19)(21,23)(22,25)(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.