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