Directional vs directionless
What is the meaning of directionless in this context
First note that the term directionless is not used (or not often at least) in the scientific literature.
I will explain the term "directionless" by talking about mutations first. Consider a given phenotype, say height. What directionless means in this context is that new mutations aren't more likely to increase than to decrease the phenotype.
Are mutations really directionless
It makes things easier to explain to someone the very basics of evolutionary processes to tell that mutations are directionless. It is however not necessarily true. When mutations are not directionless, we talk about mutation bias (see for example Eyre-Walker 1998, Harr and Schloterrer 2000 or Shah et al. 2010 ).
An obvious trait on which mutations tend to be bias is fitness. A mutation is much more likely to be deleterious than beneficial.
Is selection directional
Yes, if you talk about fitness. Selection select variants yielding that are associated to higher fitness. Note however, that if you look at, say, height, some environments may select for taller individuals, while other environments may select for shorter environments. As such selection is no "directional" on any phenotype.
Mutations and selection
Something is potentially misleading in your quote
It is true that Darwin did not quite grasp the saltatory nature of mutations, however the text puts in opposition the concept of natural selection and the one of mutation which is can be very misleading to a layman. I would need the entire text to really give you a better opinion on. Please always indicate your source!
Mutation and natural selection
In short, mutations (whether biased or not) is the ultimate source of variation on which selection can act. Selection increase the frequency of the variants (called alleles) that are associate to higher fitness. Through selection a few alleles end up to very high frequency up to the point that all individuals carry the same allele. This cause an increase in the mean fitness of the population but also removes variation (as deleterious alleles are washed out). Mutations introduce new variation that selection can select on.