Young potentials are seeking for big brands.
If a student is searching his first job, he acts like a consumer – the bigger the brand the more attractive the company is as an employer. (For the difference between employee branding and employer branding -> )
As markets are globalized the search for a future oriented employer is similar international. The main international medium is the internet. The message for enterprises is: Be found in the web. Be impressive wherever you will be found.
For search engines as guides through the internet images play only a small role; the bigger impact could be done with impressive (and unique) text. This means for the definition of a corporate identity:
There should be text elements as parts of the corporate identity and positioning, which are to be published massively throughout the web – unique and remarkable.
Booster of a strong employer brand is a branded house. Compared to a house of brands it’s simply more known and its presence in web is stronger. Umbrella brands are fine solutions.