Into what form? It has already been factorised in a way, but you can reorganis eit and factorise it in another way.
First expand all the brackets
= a²b - a²c+ b²c-b²a +c²a-c²b
= a²b -b²a +c²a - a²c+ b²c -c²b
= ab(a-b) +ac(c-a) + bc (b-c)
I'm not sure this is any better though than the original expression.
Are you sure you've stated the question exactly?