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