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