Defaults settings are: cell color is blue, cell size is 10x10 pixels square, board size is 35x35 cells square. Default pattern is Exploder and default speed is medium.
Here is a screenshot of KGameOfLife with the default settings.
The cell color is set to blue as default. You can change it to red, black or green by choosing Cell color in the Setting menu and clicking on the color you want.
Change the cell size if it does not suit you. Choices are 8x8, 10x10, 12x12, 15x15. Run KGameOfLife and choose the Settings Menu -> Cell size to do so.
It would be wise to set up the board size to the maximum you can see on your display. The Game of Life will run better on a large board because boundaries break the patterns.
Choose the Settings Menu -> Board size and set the highest you can see on your display. The change of board is a bit long to refresh on my machine, please tell me of any problem you notice.
Changing the board size will bring you to the Exploder default pattern.
You can configure the board size, the cell size, the cell color and the speed. Those parameters are saved in a config file so that your next session of KGameOfLife remember them. This file is $HOME/.kde/share/config/kgameofliferc and you can delete it if you want to go back to the default settings.
The toolbar can be hidden via the Settings menu Show toolbar menu item.