There is no such thing like a force skewing genetic mutations in a specific direction. It’s a stochastic process. You DNA is hit by an ionizing radiation and a modification ensue which can be anything and this happens randomly. Most of the time dysfunctional cells will be destroyed by the immunity system otherwise if the cells proliferate you got cancer. If it is DNA from reproduction cells, you may get a mutant or a nonviable embryo, etc.
If it’s environmental, it’s not genetic mutations. If it’s a genetic mutation, whatever the cause for the mutation (radioactivity, chemical, etc) it’s still random and the outcome cannot be predicted. It didn’t became orange on purpose.
It doesn’t change anything to the fact genetic mutations are random and there is no specific reason for one or another to occur.
“Researchers suspect rare genetic mutations caused the unusual colour, but they don’t know why”
Genetic mutations are random, so there is no reason for the orange colour.
I don’t see any interest answering this question. Mutations are random, whatever causes it. We already know many causes. From a study of the individual, you cannot identify the cause anyway. Still doesn’t make sense to me.