You may wish to think about what the effect of the different options will be. Typically, destructive, or non-editable options are given some formatting to alert the user to this. I know you're developing with Android, but the iOS design guidelines are a useful resource to be read alongside Google's Material Design spec. On the Action Sheets page, they state:
Make destructive choices prominent. Use red for buttons that perform destructive or dangerous actions, and display these buttons at the top of an action sheet.
As the previous answer states, if the choices are non-destructive, and not a Accept / Cancel type of answer, then equal formatting is preferable.
However, its best to ask what you're hoping to achieve by presenting your users with an unfamiliar, colour-filled format. Unless there is a really specific use case, it is probably best to present your users with a familiar format. In your case of an Accept / Cancel dialog, buttons are usually unboxed, and given equal formatting, using system or app standard colour for links.
If formatting must be different, you might try giving the Accept option a coloured stroke, and keeping Cancel grey?