The pervasive computing paradigm promises great abilities whenever and wherever a user goes. However, as people are shifting from the desktop to more resource-constrained devices, issues due to scarce resources may appear preventing from the use of the available services and applications. In this paper, we consider the adaptive deployment as a mainstream solution to suit service-oriented applications to different context constraints such as the users requirements, the hosts resources, the services properties and the surrounding environments. We put forward a graph-based deployment approach for service-based applications so as to make these applications adaptable to the runtime contextual constraints. We introduce the AxSeL architecture, A conteXtual Service Loader in which services and their dependencies are represented as a bidimensional graph. The dependency graph is then coloured through a process taking into account the devices, services and users constraints. This process aims to choose to load or not a service according to its execution context. A prototype based on Java and OSGi technologies is implemented in order to demonstrate and evaluate our approach.