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