Well, a literal answer would be that you could use darktable's embedded Lua scripting to apply a style to each image after import, possibly first checking the image information for camera model...
However, a more typical method would be to create auto-applied presets in each of the modules that you want to enable/disable. If you hover over the name of a style in the lighttable styles panel, a tooltip displaying a list of used modules will be displayed; these are the ones you should create presets for.
Some styles may explicitly set some modules to "off", and you generally don't need to do this with presets, with the exception of the base curve module. Since this module is currently* always enabled on newly imported images, it needs to be explicitly "disabled" by setting it to "linear" with the reset button, and making that an auto-applied preset.
* UPDATE: It looks like darktable 2.8 will have an option to disable the automatic application of the basecurve module.