Need advice for rescue cat

One of the cats we work with at the rescue centre doesn't like anything that moves. She will lash out at anything and I'm not sure why.

I've ruled out fear - if she was afraid she'd probably not lash out at the other cats (which she does)

When we give her a toy she throws it across the room growling. She will growl and hiss at anything.

Any advice on how to help her get over her demons (or whatever) and persuade her that people and other cats are not going to hurt her?