If you really wanted to, you could buy a plug in diffuser for cats, to really relax them.
We also took an old towel over to the cattery for her to lay on.
We had the diffuser when we rescued our girl. She was 9 when we got her.
We still put it on days before firework night, as shes petrified.
When we collected her from the cattery, she cried all the way home,
I closed her in a large bedroom as suggested by Cats Protection, to allow her to have her own space & familiarise herself with our smell & noises.
She scratched the bedroom door straight away & cried.
I let her out, she ran straight downstairs, layed on the lounge floor next to DD who was 2 & they watched a cartoon together.
I had put the cartoon on for DD to keep her quiet whilst I settled the cat in!