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