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